Embodiments described herein generally relate to an apparatus and a method for controlling temperature. More specifically, the embodiments relate to an apparatus and a method providing thermal control of an element of an analytical instrument.
Analytical instruments are available for performing a number of functions. Some analytical instruments perform medical tests on biological samples, such as human blood and the like. These medical tests may determine if, for example, a human blood sample is infected with the AIDS virus. To perform the medical tests, the analytical instrument may mix the blood sample with another fluid, such as reagents and the like. The blood sample reacts with the added fluid. For some of these reactions between the added fluid and the blood sample to take place as intended, it may be desirable to maintain the blood sample/added fluid mixture at a specific temperature. The mixture may need to be kept at that specific temperature for a predetermined period of time. This time period may be referred to as an "incubation period." Similar concerns about appropriate temperatures for appropriate times may relate to the blood sample and the added fluid separately before mixing.
To keep the blood sample/added fluid mixture at the desired temperature for the desired time period, the analytical instrument may be provided with a heater of sorts. The heater may be positioned near to a vessel holding the blood sample/added fluid mixture. A controller is associated with the heater for insuring that the heater supplies the vessel, and thus the mixture, with sufficient heat energy to keep the mixture at the desired, specific temperature for the desired time.
If the mixture were not kept at the specific temperature for the specific time period, then the analytical instrument may not be able to perform the medical tests as intended. For instance, the instrument may not be able to obtain correct information about the blood sample. Assuming the blood sample were infected with the AIDS virus, if the blood sample/added fluid mixture were not kept at the desired temperature for the desired time period, then the analytical instrument may tell an operator of the instrument that the blood sample is not infected with the AIDS virus. This is undesirable.
Many things may cause the mixture not to be kept at the desired temperature for the desired time period. For instance, the heater may degrade or age over time. The controller may have difficulty in controlling the heater. As the heater ages, the heater may not be able to provide the appropriate heat to the mixture for the proper time period. The heat applied to the mixture by the heater may change or vary over time. Thus, it can be appreciated that it is desirable to provide an apparatus and a method for controlling the heater and the heat applied to the blood sample, added fluid and mixture such that those things are kept at the proper temperature for the proper time period.